A student from Boston, Massachusetts, Alannah was recruited by William Miles into the Assassin Order at some point in 2017. In August, Alannah was one of the candidates chosen by a fellow Assassin Layla Hassan to accompany her on a mission to Quebec due to her expertise on ancient documents and church construction. However, as she was still in training, Alannah was not allowed to accompany Layla.
In 2018, Alannah became part of Layla's cell in search for historical artifacts, in particular the ancient scholar Herodotos' Lost Histories. Alannah served as the team's historian, providing historical details regarding Herodotos to Layla while she relived the memories of the Spartan misthios, Kassandra.
After the discovering of the location of Atlantis beneath Thera, Alannah and the cell travelled to the island using the Altaïr II, a boat belonging to Gavin Banks. When Layla was deep within Atlantis trying to unlock the throne room, the Altaïr II was attacked by Sigma Team. The cell was able to fight them off, but Kiyoshi was wounded. Alannah called Layla telling her that someone was listening in on their communications, so they were forced to go dark until it was safe to open up Atlantis.
When Layla regained communications with Alannah and her team, she informed her of her confrontation with Sigma Team's Juhani Otso Berg and the final fate of their doctor Victoria Bibeau, she then requested the team to pick her up from the vault. After this incident, Alannah and Kiyoshi's relationship with Layla became strained and they went their separate ways.
Alannah is fluent in English, Latin, Ancient Greek, and Sanskrit.
Behind the scenes
During the first modern day sequence in Odyssey, after Alannah told Layla that her great-great-grandfather was an Irish sailor and adventurer, Layla commented that Alannah makes her own luck, which was a catchphrase by Shay Cormac, an Irish Assassin who defected to the Templars. It's possible that Shay is an ancestor of Alannah.